The present invention relates to the production of a stream of chlorine dioxide. More particularly, the present invention relates to a process for efficiently generating a gaseous stream of chlorine dioxide, which stream is preferably essentially free of chlorine and inorganic salts.
Chlorine dioxide is utilized in a variety of processes including a large number of bacteriocidal applications, especially in the fields of decolorization, water treatment and odor abatement. Its usage is continuing to grow for many reasons. Due to the unstable nature of gaseous chlorine dioxide when compressed, however, it is necessary to produce chlorine dioxide on site rather than to produce it at a plant and ship it for usage when needed.
Many different methods and systems can be and have been used in the production of chlorine dioxide. For example, chlorine dioxide can be produced by the reduction of a chlorate salt by a chloride salt in an acidic medium. The chlorate salt is generally sodium chlorate, and the chloride salt is generally sodium chloride. Operable acids include hydrochloric acid, perchloric acid, phosphoric acid, and sulfuric acid. See, for example, U.S. Pat. Nos. 4,137,296 and 3,733,395. In the production of chlorine dioxide from chlorate, however, large amounts of chlorine are also generated. This chlorine must generally be removed from the product downstream of the reaction in order to provide a usable product.
The production of chlorine dioxide from chlorite is also well known. For example, see German Patent No. 1,467,024. Therein, sodium chlorite is reacted with a chlorine solution to provide chlorine dioxide product. A by-product of the reaction is an inorganic salt, i.e., sodium chloride. Removal of the inorganic salt from the chlorine dioxide product is generally required before any subsequent use of the chlorine dioxide, which removal can be costly and inefficient.
The generation of chlorine dioxide is generally carried out in an aqueous stream, thereby providing a chlorine dioxide solution as the product. If the reaction product is in the form of a gas, the chlorine dioxide is ultimately placed in solution. See, for example, U.S. Pat. No. 4,137,296. Yet, there are occasions when it would be most beneficial to employ and/or administer the chlorine dioxide as a gaseous stream. Because of the problems which can arise due to the explosiveness of chlorine dioxide in air, however, chlorine dioxide has generally been produced and maintained in an aqueous solution as a safeguard. A method and system which would allow one to generate a gaseous stream of chlorine dioxide (ClO.sub.2) in an efficient and safe manner would certainly be of great benefit to the industry. Moreover, the generation of a clean chlorine dioxide gaseous stream, i.e., a gaseous chlorine dioxide stream free of chlorine, acids, inorganic salts or any chlorite ion, would be particularly beneficial, as such a clean gaseous stream would be eligible for many additional applications.
Accordingly, it is an object of the present invention to provide a method for efficiently and safely generating a gaseous stream of chlorine dioxide for subsequent utilization and application.
It is another object of the present invention to provide an efficient method for generating a gaseous stream of chlorine dioxide, which stream of chlorine dioxide is substantially clean. More specifically, the gaseous stream of chlorine dioxide would be substantially free of chlorine, inorganic salts, chlorite ion and acids.
Yet another object of the present invention is to provide a method and system for generating a clean gaseous stream of chloride dioxide which is simple and efficient, yet safe.
These and other objects, as well as the scope, nature and utilization of the invention, will become apparent to those skilled in the art from the following description, the drawing, and the appended claims.